This invention relates to a method of manufacturing an antenna structure for the transmission and processing of electromagnetic microwave signals.
This invention also relates to an antenna structure comprising a distribution network for the transmission and processing of electromagnetic microwave signals. The antenna structure is constructed as a plate structure, in which there are cut-outs and which comprises at least one intermediate electrically-conductive plate with surrounding electrically-conductive plates attached on each side of each intermediate plate. Each side of these surrounding plates is in contact with one or the other side of each intermediate plate.
The most commonly used antenna structure for microwave signals is the reflector antenna with a three-dimensionally curved reflector, normally in the shape of a parabola, with a feeder situated at the focus. However, this type of antenna takes up a lot of room, particularly on account of its large depth in relation to its height.
Within wireless information transmission, e.g. within radio link communication, ever-increasing demands are being made for thin plate structures, which are able to fit more easily into the surroundings.
Previously flat conductor antenna have been produced based upon microstrip technology which, although it is flat, involves large losses and can lead to complicated solutions, particularly for high frequencies.
U.S. Pat. No. 3,925,883 shows a wave guide device which is formed by bending a metal plate and fixing it to other plates. A component of the wave guide device can be constructed of a plate structure with a number of plates with holes laid on each other which form a microwave flange. The holes in the plates have, however, relatively similar configuration whereby a hole in an intermediate plate is not limited to any significant degree by the surrounding plates, which thereby cannot form any wave guide structure in the principal plane of the plates. The wave conductor device is not an antenna structure.
A wave guide device which is constructed as a plate structure is known from SWEDISH PATENT DOCUMENT SE-C2-505 504. This device has a base plate in which wave conductors and wave conductor components are cut out. In this device only one surrounding plate forms the limit surface for one and the same hole. Nor does this wave guide device consist of an antenna structure.